The present invention relates in general to devices for limiting the range of projectiles and, in particular, to a fin disengagement device for limiting the range of a projectile.
Most prior devices for limiting the range of projectiles create high drag bodies by changing the shape of the nose section of the projectile. Other devices break up or separate the projectile for the purpose of creating damage to the desired target.
U.S. Pat. No. 3,580,179 discloses ammunition for target practice or other short-range purposes. The projectile""s nose either disintegrates and/or is jettisoned off to create drag thereby altering the projectile""s aerodynamic coefficients and ultimately decreasing its range.
U.S. Pat. No. 4,140,061 describes a short-range discarding-sabot training practice round and self-destruct subprojectile. A disintegrating nose cone is used to induce instability to the projectile.
U.S. Pat. No. 4,215,632 shows an exercise projectile, especially of the discarding sabot type. This invention harnesses the gun gas pressure and uses it to separate the projectile parts in-flight.
U.S. Pat. No. 4,362,107 discloses a practice projectile that breaks apart on impact.
U.S. Pat. No. 4,553,482 describes a practice projectile that uses the tracer to start a pyrotechnic delay to separate projectile parts.
U.S. Pat. No. 4,724,765 shows a projectile comprising a pyrotechnic charge. The projectile uses a pyrotechnic delay that is started on launch by the gun gases to ignite a charge located in the middle of the projectile""s body.
No previous inventions were found that disengage just the fin section to destabilize the projectile. Most prior inventions alter the projectile""s flight characteristics by making changes to the projectile""s nose or by breaking up the projectile""s body. The present invention does not create shrapnel when disengaged since the fin discard charge is designed to separate the fin section intact from the projectile""s rod body. It has been proven by simulation and experimentation that jettisoning off the projectile""s fin decreases its range much more dramatically than by blunting the projectile""s nose.
The present invention includes a device that can be integrated into any fin-stabilized or flare-stabilized projectile for the purpose of separating the projectile""s fin or flare section from the projectile""s body.
During the initial portion of the flight, the trajectory of the projectile with the fin disengagement device installed will be closely matched to the tactical projectile that it resembles. At a predetermined time along the trajectory, the safe and arm electronic system initiates an energetic material to separate the fin from the rod. Once the fin is discarded, the projectile rod becomes aerodynamically unstable and tumbles, thus limiting its range.
One application of the invention is to create a range-limited training practice projectile that can be made similar in mass, external shape, and aerodynamic properties to the tactical kinetic energy projectile that it replicates. The practice projectile may be constructed to look like a sub-caliber fin-stabilized tank projectile and may be made of steel. The invention can also take the form of a replacement kit that is used to limit the range of existing projectiles.
The invention uses an electronic arming circuit, for example, the electronic arming circuit disclosed in copending U.S. patent application Ser. No. 09/707,289 entitled xe2x80x9cAn Electronic Arming Apparatus for Initiating Propellants and Explosives,xe2x80x9d having as inventors B. Davis, E. Bukowski, and W. D""Amico, which is hereby expressly incorporated by reference.
Further objects, features and advantages of the invention will become apparent from the following detailed description taken in conjunction with the following drawing.